An electric-powered vehicle is mounted with a power storage device (such as secondary battery or capacitor for example) and travels by using driving force generated from electric power stored in the power storage device. The electric-powered vehicle includes, for example, electric vehicle, hybrid vehicle, fuel-cell vehicle and the like.
In recent years, a technique has been proposed for charging a power storage device mounted on such vehicles as described above by a commercial power supply having a high power generation efficiency. With this technique, increase in fuel consumption efficiency of the hybrid vehicle for example can be expected. In particular, attention is being given to a technique for charging a power storage device mounted on an electric-powered vehicle by a commercial power supply (a source of a relatively low voltage such as 100 V or 200 V, for example) providing electric power to each household. In the following, a vehicle having a power storage device such as battery mounted on the vehicle and chargeable by means of a power supply outside the vehicle is also referred to as “plug-in vehicle”.
In the vehicle of the above-described type, generally the power storage device is charged by connecting a charge cable to a connector provided to the vehicle. Regarding a technique for charging a power storage device mounted on a vehicle by means of an external power supply, Japanese Patent Laying-Open No. 7-123519 (Patent Document 1) for example discloses a charging control device that is activated immediately after a charger is connected to the device, and turns on a relay so that a conductive line used for charging is set into a chargeable state.    Patent Document 1: Japanese Patent Laying-Open No. 7-123519    Patent Document 2: Japanese Patent Laying-Open No. 7-46711    Patent Document 3: Japanese Patent Laying-Open No. 5-308732    Patent Document 4: Japanese Utility Model Laying-Open No. 6-2948